None.
Not Applicable.
1. Field of the Invention
This invention relates generally to an operator input interface for a bulk material baling machine that uses a control system incorporating user input parameters for process variables.
2. Related Art
Wire baling of bulk materials benefits from increased speed and reduced materials cost through automation. Bulk materials include fibrous bulk materials such as cotton and nylon. Fibrous materials are commonly formed into bales by simultaneous compression and binding. There is a continuing need in the automated baling art to improve the efficiency, reliability and accuracy of the bale binding process.
Baling wire performance requirements vary depending upon the bulk material being baled. Such requirements range from industry standard specifications to general operational parameters, such as minimum speeds required for profitability. The Cotton Council issues standard baling constraints specifying particular ranges for the length of wire around the bale and the tension that the wire must withstand.
Current automated baling machines use an articulated track to guide wire around bales of bulk material, while that bale is under compression. Part of the wire guide track in current automated balers must be removable to a second position after the ends of the baling wire have been tied together, in order to allow ejection of the bale and insertion into the baler of the next unit of material for baling. Material to be baled is typically introduced into the automatic baler under vertical compression. Typical pressures for an industry standard 500 pound, 20xc3x9754 inch bale are in excess of 300 tons. Horizontal plates called follower blocks apply compression through platens which contact the surface of the cotton or other material being compressed. The Platens incorporate slots which ran lateral to the longitudinal axis of the bale. The Industry Standard number of binding wires for cotton bales is six. Accordingly there are six slots in the platens. These allow the baling wire to be wrapped around the bale while it is still under compression. The lateral slots have lateral channels behind them for insertion of wire guide tracks in both the upper and lower platens in automatic balers.
In order to loop baling wire around bulk material to be baled, release it from a guide track and knot the ends, tension must be generated on the wire. Likewise, in order to properly knot the ends of the wire, tension must be maintained in the twisting procedure that generates the knot. These tensions must be maintained within prescribed ranges to optimize efficiency and to produce a final bale compliant with industry standards. Certain knotting speeds must be avoided because too much speed in the twisting procedure produces metal fatigue. Too great a degree of tension overall can generate weaknesses or wear-points in the baling wire, or can generate wear in the wire guide tracks or other parts of the automated baling machine.
Current automated baling machines operate with a certain degree of inefficiency. Automated baling machines would benefit from more precise control of such variables as tension, speed and wire position. Precise control of process variables would be best achieved with a system whereby a user may input precise parameters for those variables and whereby precise data feedback is available to the user. Prior art balers have had no such system.
There is a need in the art to increase the precision of controls in order to maximize speed while maintaining adequate compliance with industry standards for material bales produced, in order to minimize wear and damage and to maximize efficiency. There is a further need for more individual user control of operations.
It is in the view of the above problems that the present invention was developed. The invention is a graphical operator interface for a control system that governs an automatic bulk material baling apparatus. The control system incorporates Programmable Logic Controllers (xe2x80x9cPLCsxe2x80x9d) and data structures within memories capable of controlling a plurality of process control variables. Each bale wire loop on a bulk material bale is produced by an individual xe2x80x9chead.xe2x80x9d Each head incorporates drive wheels and a fastener or xe2x80x9cknotter.xe2x80x9d Each set of drive wheels and each fastener of the present invention is powered with independent electro-servo motors. Each motor is considered an xe2x80x9caxisxe2x80x9d of control. Each servo motor has operation variables such as speed and torque. In addition, each head uses a tensioning gripper, moveable tensioning pins, a cutter and in some cases limit switches, all of which are controllable by the control system of the present invention. The dynamic memory of the control system is configurable to precisely control all relevant variables according to operator input parameters.
Control is affected through the PLC of the control system. Each axis of control has a separate memory space in the control system, so that each head may be controlled individually. The PLC and memory of the present control system track the precise position of the drive wheel shafts and fastener head shafts at all times to within a thousandth of an inch. Thus, the control system can precisely measure and control position and speed. The system constantly measures the amperage of current being used by the electro-servo motors controlling the drive wheels and tying cylinders of the knotter. This current quantity corresponds to a quantity of torque in a known ratio. Torque levels may be pre-configured at optimal parameters in the control system""s memory. Precise torque control benefits wire tensioning and knot tying.
Configuring the variable parameters like torque and wire position in the memory data structure is achieved through the user interface of the present invention.
In operation, the position tracking of the present control system allows precise control of the speed of the progress of baling wire around the bulk material. Upon completion of its loop around the bulk material, the baling wire progress is arrested by means of electro servo position data feedback. The wire is then gripped with a tensioning gripper. The drive wheels are then reversed in order to generate a pre-configured degree of tension on the baling wire. This tension is precisely controlled by the control system of the present invention with its pre-configured memory of the desired torque on the drive wheels, which is precisely monitored by constant servo motor feedback of the amperage drawn. Similarly, current feedback is monitored in the fastener electro-servo motor, which drives rotational tying cylinders. Both torque control and position control are used by the control system to efficiently control the tying of a knot in the baling wire in a fashion that maximizes speed while remaining within industry standard strength and tension limits. After looping the bale wire, releasing the wire guide track, tying the knot and cutting the wire, the control system is pre-configured to release the bale wire loops and allow the completed bale to be ejected.
The baling apparatus control system is also pre-configured to control the sequential progression of the bale compression apparatus, moveable guide track sections and ejection apparatus. This is done through permissive process control memory which sequentially signals activation of the next step in the process upon receipt of a signal that the previous step is complete. Process status is constantly displayed to the operator by the present invention.
Wire feed position, torque and speed, knotter position, torque and speed, tensioning torque and other process variables are all configured in memory by operator interface of the present invention. Storage and feedback of these variables is also performed by the present invention.
In operation, a user views a touch screen series and inputs selected parameters in field windows for each variable. Further control is available through data feedback, manual override and a emergency settings in the present invention as well.
Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings.